Myth: You should never 'cheat' on a diet.

Truth: It's perfectly fine to go off your healthy eating plan every once in a while, Nichola Whitehead, a registered dietitian and nutritionist with a practice in the UK, tells Business Insider.

"It's alright to overeat occasionally," says Whitehead. "It's overeating consistently day in and day out over the long term that causes weight gain."

If you've managed to switch from a diet heavy in red meat and processed carbohydrates to eating mostly vegetables, whole grains, and lean proteins, you've already done the majority of the work, Whitehead says.

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Myth: Counting calories is the best way to lose weight.

Samantha Lee/Business Insider

Truth: Although counting calories can be a useful tool in a bigger toolkit for weight loss, it is not a perfect solution for healthy eating, especially when it's used in isolation.

That's because restricting calories doesn't take into account all the aspects of a food that are required to fuel your body, from protein and carbohydrates to vitamins and minerals. Whitehead summarizes the problem this way: "While calories are important when it comes to losing, maintaining, or gaining weight, they are not the sole thing we should be focusing on when it comes to improving our health."

Myth: Cleanses and detoxes are a good way to jump-start a diet.

Unless you've been poisoned, you have a built-in, super-efficient system for filtering out most of the harmful substances you eat. It's made up of two toxin-bashing organs: the liver and the kidneys. Our kidneys filter our blood and remove any waste from our diet, and our livers process medications and detoxify any chemicals we ingest. Paired together, these organs make our bodies natural cleansing powerhouses. Juice cleanse? No thanks.

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Myth: Adding a supplement to your weight-loss plan is a good idea.

Reuters

Truth: Decades of research has failed to find substantial evidence that supplements do any significant good. On the contrary, some of them can do significant harm.

These supplements are "the most lawless of all the categories and where the most problems turn up," Austin said.

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Myth: A diet that works for one person should work just as well for others.

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Truth: No two bodies are the same, so there's no single best diet.

Everything from an individual's genetics to their taste preferences and even their schedule can influence the type of healthy eating plan that works for them. The most important factor to look for in a healthy eating plan, studies suggest, is a routine you can stick with. This can mean trying out a few different options until you find one you like and can maintain.

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Myth: Egg whites are healthier than whole eggs.

Truth: People tend to avoid whole eggs because of their high cholesterol content, but recent research suggests that the cholesterol from our diets doesn't have much of an effect on the level of cholesterol in our blood.

Most of the early research suggesting that cholesterol consumption was unhealthy was done in rabbits, who don't eat any animal products.

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Myth: Avoiding gluten is a good way to keep your digestive system healthy.

Studies show that most people suffer from slight bloating and gas when they eat, whether they consume wheat or not.

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Myth: Almond milk is healthier than regular milk.

AP

Truth: Alternatives to dairy aren't always nutritionally superior.

Compared with a glass of low-fat milk, which has about 8 grams of protein, almond milk has none. Plus, most of the vitamins in almond milk are added during the production process, which some studies suggest can make it harder for the body to absorb and hold onto the nutrients. Soy milk, on the other hand, is roughly on-par with low-fat milk, serving up the same amount of protein plus some naturally occurring micronutrients from soy beans.

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Myth: Juices are a good replacement for meals.

Truth: While juice has some vitamins and in some cases even a small amount of protein, research shows that the best way to get those nutrients is to eat a balanced diet full of vegetables, fruits, and whole grains.

More importantly, juicing fruit removes most of the fiber, which is the key ingredient that keeps you feeling full until your next meal. This is one of the reasons calories from sweetened beverages are often referred to as "empty calories," since they can increase hunger pangs and mood swings and leave you with low energy levels.

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Myth: You should steer clear of MSG.

Will Wei, Business Insider

Truth: Monosodium glutamate is an ingredient added to many foods to enhance their flavor, and it's completely safe to ingest.

MSG is often associated with a series of symptoms including numbness at the base of the neck and a general sense of fatigue that are commonly lumped together and called "Chinese Restaurant Syndrome." Eating too much, regardless of the amount of MSG, is the more likely culprit here.

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Myth: Microwaving your food destroys its nutrients.

Microwave ovens cook food using energy waves that cause the molecules in food to vibrate quickly, building up their energy as heat. Some nutrients begin to disintegrate when heated, whether from a microwave, a stove, or oven. But since microwave-cooking times are typically shorter than oven-cooking times, microwaving something may actually keep more of its vitamins intact.

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Myth: Chia seeds, apple cider vinegar, and mushrooms are superfoods.

Truth: While certain foods have more health benefits than others, there is no legal or medical definition for what counts as a "superfood." Nutritionists and public-health experts rarely use the term. So if anyone starts tossing that word around, there's probably a good chance they're not as knowledgeable as they claim.